A major drawback of industrial and commercial refrigeration systems which utilize ammonia as a refrigerant is the high cost of installation, operation, and maintenance. The main reason for these high costs lies in the fact that conventional ammonia refrigeration systems are designed for relatively high discharge pressures, and require the use of liquid pumps and large accumulators, because the processing, cooler, or product freezer units do not completely vaporize the liquid ammonia into gas. Thus, liquid ammonia will flow through the system in combination with ammonia gas. This incomplete vaporization of the ammonia is the main cause for the high cost of installation, operation, and maintenance of ammonia type refrigeration systems currently on the market.
Because liquid ammonia must be moved throughout the system, liquid ammonia pumps or pumper drums must be used to pump the liquid, requiring higher pressures throughout the system. In addition, pumping liquid throughout the system requires larger accumulators and larger pipes throughout the system, thereby adding to the installation costs as well as operating costs.